Solid thickening and methane production of livestock wastewater using dissolved carbon dioxide flotation

2015 ◽  
Vol 51 (1) ◽  
pp. 17-25 ◽  
Author(s):  
Dong-Heui Kwak ◽  
Soo-Wan Chae
Keyword(s):  
Wastewater Treatment ◽  
Methane Production ◽  
Wastewater Treatment Plants ◽  
Biochemical Methane Potential ◽  
Livestock Wastewater ◽  
Co2 Gas ◽  
Dissolved Carbon ◽  
Dissolved Carbon Dioxide ◽  
Methane Potential ◽  
Sludge Thickening

Dilute manure is classified as wastewater due to the large quantity of water used in livestock production in Korea. Livestock wastewater treatment is required in order to reduce high moisture content and treat fluids discharged from the digestion process. In livestock wastewater treatment plants, large quantities of CO2 gas are produced at combined heat and power facilities as well as in the anaerobic digestion (AD) process. This gas produced during livestock wastewater treatment can be used as a separator of solids from liquid in wastewater. In this study, a flotation system using recycled CO2 gas was used for sludge thickening. An anaerobic toxicity assay (ATA) and a biochemical methane potential assay were used to assess the toxicity impact of recycling CO2 on the methane production potential. ATA experiments confirmed that CO2 toxicity did not impair the AD process. The tests indicated that the cumulative methane yield from influent livestock manure enriched with CO2 was approximately 190 mL-CH4/g-VSadded. The data demonstrated the potential of using dissolved CO2 flotation in the AD of diluted livestock wastewater.

Bacteria reduction and nutrient removal in small wastewater treatment plants by an algal biofilm

2003 ◽  
Vol 47 (11) ◽  
pp. 195-202 ◽  
Author(s):  
G. Schumacher ◽  
T. Blume ◽  
I. Sekoulov
Keyword(s):  
Carbon Dioxide ◽  
Wastewater Treatment ◽  
Nutrient Removal ◽  
Wastewater Treatment Plants ◽  
Secondary Effluent ◽  
Dissolved Carbon ◽  
Attached Algae ◽  
Dissolved Carbon Dioxide ◽  
Algal Biofilm ◽  
Faecal Bacteria

Attached algae settlement is frequently observed in effluents of wastewater treatment plants at locations with sufficient sunlight. For their growth they incorporate nutrients and the surface of the algal biofilm accumulates suspended solids from the clarified wastewater. During the photosynthesis process of algal biofilms oxygen is produced while dissolved carbon dioxide is consumed. This led to an increasing pH due to the change of the carbon dioxide equilibrium in water. The high pH causes precipitation of dissolved phosphates. Furthermore an extensive removal of faecal bacteria was observed in the presence of algae, which may be caused by the activity of algae. The experimental results indicate the high potential of these attached algae for polishing secondary effluent of wastewater treatment plants. Especially for small wastewater treatment plants a post connected stage for nutrient removal and bacteria reduction can be developed with the aid of an algal biofilm.

scholarly journals Influence of conditioning agents and enzymic hydrolysis on the biochemical methane potential of sewage sludge

2013 ◽  
Vol 68 (7) ◽  
pp. 1622-1632 ◽  
Author(s):  
Elena Marañón ◽  
Luis Negral ◽  
Yolanda Fernández-Nava ◽  
Leonor Castrillón
Keyword(s):  
Sewage Sludge ◽  
Methane Production ◽  
Wastewater Treatment Plants ◽  
Solid Phase ◽  
Enzymic Hydrolysis ◽  
Biochemical Methane Potential ◽  
General Improvement ◽  
Methane Potential ◽  
Pre Treatment ◽  
Cationic Polyelectrolytes

Biochemical methane potential (BMP) tests have been carried out on sewage sludge from two wastewater treatment plants to assess the effect of additives (FeCl3 and two cationic polyelectrolytes) used in sludge dewatering. BMP tests were also carried out on the concentrated solid phase from the enzymic hydrolysis pre-treatment (42 °C, 48 h). FeCl3 had no significant effect on specific methane production, obtaining 242–246 LCH4/kgVSo. The effect of the combination of polyelectrolyte and FeCl3 depended on the polyelectrolyte and the sludge, but generally led to an increase in specific methane production (25–40%). When enzymic hydrolysis was applied as a pre-treatment, specific methane production increased from 6.8% in the sludge containing FeCl3 to 20% in the sludge without FeCl3, although the increases were not statistically significant. In terms of LCH4/kgVSrem, a general improvement was achieved both by means of additives and by enzymic hydrolysis. However, this improvement was only significant in the case of sludge which had undergone previous enzymic hydrolysis (62%) and in the untreated sludge containing a polyelectrolyte and FeCl3 (24%). Cationic polyelectrolytes inhibited solid–liquid separation during enzymic hydrolysis and, although the presence of only FeCl3 did not affect this separation, a significant decrease (32%) in LCH4/kgVSrem was observed.

scholarly journals Occurrence and Removal of Veterinary Antibiotics in Livestock Wastewater Treatment Plants, South Korea

Processes ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 720 ◽  
Author(s):  
Jin-Pil Kim ◽  
Dal Rae Jin ◽  
Wonseok Lee ◽  
Minhee Chae ◽  
Junwon Park
Keyword(s):  
Wastewater Treatment ◽  
South Korea ◽  
Removal Efficiency ◽  
Wastewater Treatment Plants ◽  
Batch Reactor ◽  
Veterinary Antibiotics ◽  
Livestock Wastewater ◽  
Treatment Processes ◽  
Removal Efficiencies ◽  
A2o Process

In this study, livestock wastewater treatment plants in South Korea were monitored to determine the characteristics of influent and effluent wastewater, containing four types of veterinary antibiotics (sulfamethazine, sulfathiazole, chlortetracycline, oxytetracycline), and the removal efficiencies of different treatment processes. Chlortetracycline had the highest average influent concentration (483.7 μg/L), followed by sulfamethazine (251.2 μg/L), sulfathiazole (230.8 μg/L) and oxytetracycline (25.7 μg/L), at five livestock wastewater treatment plants. Sulfathiazole had the highest average effluent concentration (28.2 μg/L), followed by sulfamethazine (20.8 μg/L) and chlortetracycline (11.5 μg/L), while no oxytetracycline was detected. For veterinary antibiotics in the wastewater, a removal efficiency of at least 90% was observed with five types of treatment processes, including a bio-ceramic sequencing batch reactor, liquid-phase flotation, membrane bioreactor, bioreactor plus ultrafiltration (BIOSUF) and bio best bacillus systems. Moreover, this study evaluated the removal efficiency via laboratory-scale experiments on the conventional contaminants, such as organic matter, nitrogen, phosphorus and veterinary antibiotics. This was done using the hydraulic retention time (HRT), under three temporal conditions (14 h, 18 h, 27 h), using the anaerobic–anoxic–oxic (A2O) process, in an attempt to assess the combined livestock wastewater treatment process where the livestock wastewater is treated until certain levels of water quality are achieved, and then the effluent is discharged to nearby sewage treatment plants for further treatment. The removal efficiencies of veterinary antibiotics, especially oxytetracycline and chlortetracycline, were 86.5–88.8% and 87.9–90.8%, respectively, exhibiting no significant differences under various HRT conditions. The removal efficiency of sulfamethazine was at least 20% higher at HRT = 27 h than at HRT = 14 h, indicating that sulfamethazine was efficiently removed in the A2O process with increased HRT. This study is expected to promote a comprehensive understanding of the behavior and removal of veterinary antibiotics in the livestock wastewater treatment plants of South Korea.

scholarly journals Evaluation of Feasibility of Using the Bacteriophage T4 Lysozyme to Improve the Hydrolysis and Biochemical Methane Potential of Secondary Sludge

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3644
Author(s):  
Sangmin Kim ◽  
Seung-Gyun Woo ◽  
Joonyeob Lee ◽  
Dae-Hee Lee ◽  
Seokhwan Hwang
Keyword(s):  
Cell Wall ◽  
Bacterial Cell ◽  
Wastewater Treatment Plants ◽  
Biogas Production ◽  
Bacteriophage T4 ◽  
Suspended Solid ◽  
T4 Lysozyme ◽  
Biochemical Methane Potential ◽  
Secondary Sludge ◽  
Methane Potential

Anaerobic digestion (AD) of secondary sludge is a rate-limiting step due to the bacterial cell wall. In this study, experiments were performed to characterize secondary sludges from three wastewater treatment plants (WWTPs), and to investigate the feasibility of using bacteriophage lysozymes to speed up AD by accelerating the degradation of bacterial cell walls. Protein was the main organic material (67.7% of volatile solids in the sludge). The bacteriophage T4 lysozyme (T4L) was tested for hydrolysis and biochemical methane potential. Variations in the volatile suspended solid (VSS) concentration and biogas production were monitored. The VSS reduction efficiencies by hydrolysis using T4L for 72 h increased and ranged from 17.8% to 26.4%. Biogas production using T4L treated sludges increased and biogas production was increased by as much as 82.4%. Biogas production rate also increased, and the average reaction rate coefficient of first-order kinetics was 0.56 ± 0.02/d, which was up to 47.5% higher compared to the untreated samples at the maximum. Alphaproteobacteria, Betaproteobacteria, Flavobacteriia, Gammaproteobacteria, and Sphingobacteriia were major microbial classes in all sludges. The interpretation of the microbial community structure indicated that T4L treatment is likely to increase the rate of cell wall digestion.

Assessing the role of biochemical methane potential tests in determining anaerobic degradability rate and extent

2011 ◽  
Vol 64 (4) ◽  
pp. 880-886 ◽  
Author(s):  
P. D. Jensen ◽  
H. Ge ◽  
D. J. Batstone
Keyword(s):  
Parameter Estimation ◽  
Methane Production ◽  
Estimation Method ◽  
Test Method ◽  
Continuous Systems ◽  
Batch Test ◽  
Biochemical Methane Potential ◽  
First Order ◽  
Methane Potential ◽  
The Impact

The biodegradability and bioavailability of hydrolysis-limited substrates under anaerobic (and aerobic) conditions can be represented by two key parameters – degradability (fd), or the percentage that can be effectively be destroyed during digestion, and first order hydrolysis coefficient (khyd), or the speed at which material breaks down. Biochemical methane potential (BMP) testing uses a batch test (in triplicate), and by fitting against a first order model, can fit both parameters in the same test. BMP testing is now being widely used for anaerobic process feasibility and design purposes, and standardisation efforts are ongoing. In this paper, we address a number of key issues relating to the test method and its analysis. This includes proposal of a new fitting and parameter estimation method, evaluation of the impact of inoculum to substrate ratio on fitted parameters, and comparison to performance in continuous systems. The new parameter estimation technique provides an estimate of parameter uncertainty and correlation, and is clearly more suitable than model transformation and linear regression. An inoculum volume ratio of at least 50% (2:1 on VS basis) was required on a cellulose substrate to use methane production as primary indicator, as found by comparing methane production and solubilisation of cellulose. Finally, on a typical material, waste activated sludge, the batch test was slightly conservative in terms of degradability and rate, indicating a bias in the BMP test. The test is a cost-effective and capable method to evaluate potential substrates, but it should be noted that it is generally conservative, especially if sub-optimal inoculum is used.

A simple empirical model for the clarification-thickening process in wastewater treatment plants

2014 ◽  
Vol 71 (3) ◽  
pp. 366-372
Author(s):  
Y. K. Zhang ◽  
H. C. Wang ◽  
L. Qi ◽  
G. H. Liu ◽  
Z. J. He ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Empirical Model ◽  
Wastewater Treatment Plants ◽  
Volume Index ◽  
Compression Zone ◽  
Efficient Operation ◽  
Secondary Settling ◽  
Sludge Thickening ◽  
Simple Empirical Model

In wastewater treatment plants (WWTPs), activated sludge is thickened in secondary settling tanks and recycled into the biological reactor to maintain enough biomass for wastewater treatment. Accurately estimating the activated sludge concentration in the lower portion of the secondary clarifiers is of great importance for evaluating and controlling the sludge recycled ratio, ensuring smooth and efficient operation of the WWTP. By dividing the overall activated sludge-thickening curve into a hindered zone and a compression zone, an empirical model describing activated sludge thickening in the compression zone was obtained by empirical regression. This empirical model was developed through experiments conducted using sludge from five WWTPs, and validated by the measured data from a sixth WWTP, which fit the model well (R2 = 0.98, p < 0.001). The model requires application of only one parameter, the sludge volume index (SVI), which is readily incorporated into routine analysis. By combining this model with the conservation of mass equation, an empirical model for compression settling was also developed. Finally, the effects of denitrification and addition of a polymer were also analysed because of their effect on sludge thickening, which can be useful for WWTP operation, e.g., improving wastewater treatment or the proper use of the polymer.

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